Emoji keyboard jumps back to letters after less than a second

On the iPhone of my wife the Riot client gets in a strange state with the keyboard. In this state, the emoji keyboard can't be selected anymore.

There are two keyboards configured, the German QWERTZ keyboard and the Emoji keyboard. So there is a simple switch button in IOS in this configuration. In the broken state, whenever the Emoji keyboard should be selected by the "Emoji" keyboard switch button, it shows the Emojis very short and immetiately jumps back to the letter keyboard. This issue can only be solved by shutting down the Riot app (by "shifting" it to the top in the task switcher) and restarting it - until it happens again.

We still try to reproduce how to get into that state, because I'm also doing some software and I know how hard it is to find a bug without concrete steps how to reproduce the issue. As for now I can't tell exactly how the App gets into that state. Facts are:

- She's dictating 95%, it might be related to the use of dictation
- No other Apps (iMessage, WhatsApp, Facebook Messenger, Mattermost) are suffering from that bug with the same way of working - only Riot. That lets me think about an App bug instead an IOS issue. Also just a restart of Riot solves it (temporary), a restart of the iPhone is not needed.
- Device is an iPhone 8 Plus, IOS 11.4.1

We will continue to investigate how to reproduce getting into the buggy state as it's really annoying - and update this ticket as we have new findings. But I decided to file the issue yet, maybe a dev has an idea what could cause the unwanted keyboard backswitching.